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Biomedical subjects

T Nishikiori

Publications and source records attributed to T Nishikiori.

At least 19 recordsLinked to original sources
PubMed1998

Cell cycle arrest and antitumor activity of pironetin and its derivatives.

The biological effects of pironetin and its derivatives on cell cycle progression and antitumor activity were studied. At 10-20 ng/ml, both pironetin and its demethyl derivative, NK10958P completely inhibited the cell proliferation of 3Y1 cells, however, epoxypironetin showed only a weak inhibitory activity. The cell cycle analysis revealed that these compounds arrested the cell cycle progression at the M-phase in a dose-dependent manner. These antiproliferative effects of pironetin were also observed in the range 5-25 ng/ml with several tumor cell lines. In CDF1-SLC mice bearing P388 leukemia cells, the intraperitoneal administration of 6.3 mg/kg pironetin over a 5-day period showed a moderate antitumor effect (T/C, 128%). As the chemical structure of pironetin is different from other M-phase inhibitors such as colchicine or vinblastine, pironetin will be the lead compound for a potential new antitumor drug.

Animals↗
PubMed1997

NF00659A1, A2, A3, B1 and B2, novel antitumor antibiotics produced by Aspergillus sp. NF 00659. I. Taxonomy, fermentation, isolation and biological activities.

Five novel cytotoxic antibiotics, NF00659A1 (1), A2 (2), A3 (3), B1 (4) and B2 (5) were discovered. They were isolated from a culture mycelium of Aspergillus sp. These compounds were proved to have 4,5-seco-tricyclic diterpene alpha-pyrone structure by spectroscopic analyses. They showed potent antitumor activities against human ovarian carcinoma A2780 and human colorectal adenocarcinoma SW480 cells, but did not show any antimicrobial activities at 1,000 micrograms/ml against Gram-positive and Gram-negative bacteria, yeasts and fungi.

Adenocarcinoma↗
PubMed1997

NF00659A1, A2, A3, B1 and B2, novel antitumor antibiotics produced by Aspergillus sp. NF 00659. II. Structural elucidation.

NF00659A1, A2, A3, B1 and B2, having insecticidal and antitumor activities, were isolated from a culture mycelium of Aspergillus sp. NF 00659. The novel structure of NF00659s were determined mainly by spectroscopic studies including various NMR measurements. NF00659s have a common structure which consists of acyl, alpha-pyrone and 4,5-seco-tricyclic diterpene moieties.

Antibiotics, Antineoplastic↗
PubMed1996

Structural determination of stevastelins, novel depsipeptides from Penicillium sp.

Structures of novel immunosuppressants, stevastelin A, B and B3(1) were determined by their spectroscopic and chemical studies. Three stevastelins were shown to be cyclic depsipeptides composed of a fatty acid and three amino acid moieties. The sequence of these moieties was determined to be as 3,5-dihydroxy-2,4-dimethylstearylvalylthreonyl (or O-sulfonylthreonyl in stevastelin A)-O-acetylserine. Cyclic structures were shown to be formed by ester linkages between the carboxylic group of the O-acetylserine moiety and the 5-hydroxy group of the fatty acid moiety in stevastelin A and B, and the 3-hydroxy group of the fatty acid moiety in stevastelin B3.

Anti-Bacterial Agents↗
PubMed1995

[Serum cardiac troponin-T in coronary artery bypass graft and mitral valve replacement].

Serum cardiac troponin-T was measured to evaluate perioperative myocardial injury in heart surgery. Twelve patients of coronary artery bypass graft (CABG) and nine of mitral valve replacement (MVR) were selected and the measurements were performed at 3 points-before, as well as after the surgery and on the first postoperative day. Elevated serum levels of troponin-T were observed in postoperative measurement in both groups (CABG 2.98 +/- 1.44, MVR 2.57 +/- 0.52 ng.ml-1), where all the preoperative values were less than 0.1 ng.ml-1. On the first postoperative day, CABG group showed a higher serum level of troponin-T than MVR group (6.05 +/- 4.16 vs. 2.57 +/- 2.12 ng.ml-1, P < 0.05 respectively). Taking another myocardial marker, such as CK-MB or myosin light chain I, into consideration, these data indicate that myocardial injury occurs during heart surgery and the grade of injury is severer in CABG than in MVR.

Aged↗
PubMed1992

44-Homooligomycins A and B, new antitumor antibiotics from Streptomyces bottropensis. Producing organism, fermentation, isolation, structure elucidation and biological properties.

Oligomycin antibiotics, 44-homooligomycin A (NK86-0279 II) and B (NK86-0279 I) are newly discovered antitumor antibiotics with the substitution of ethyl for methyl at carbon 26. They were isolated from the culture broth of Streptomyces bottropensis NK86-0279. The structure of these two compounds was deduced by spectroscopic and X-ray crystallographic analyses. These antibiotics showed potent antitumor activities against various tumor cells in vitro, and were active against Colon 26 carcinoma in vivo. Although they showed no activity at 1,000 micrograms/ml against Gram-positive and Gram-negative bacteria and yeast, they have antifungal activity.

Antibiotics, Antineoplastic↗